The present invention relates to a printing system which can be suitably used to secure confidential information or the like contained in print sheets and to reuse print sheets having one side thereof already used.
In recent years, from the perspectives to protect environments, save resources, and reduce expenses, attempts have been increased to effectively use print sheets by printing one side of the print sheet of which the other side is already printed, that is, unused side of the print sheet. However, if confidential information is contained in the print result printed on the used side of the sheet, there are possibilities that the confidential information may leak out. Therefore, there is a problem that in order to avoid the information leak out, it is necessary to check whether or not print sheets to be reused contain confidential information and then remove those used print sheets which contain confidential information.
To solve such problem, for example, JP-A-2000-159410 specification proposes a sheet sorting apparatus that beforehand registers and stores a particular mark such as “Company Confidential” which indicates containment of confidential information, and switches over a print sheet transportation path to a shredder side to inhibit a used print sheet from being reused when the particular mark is detected on at least one side thereof.